Risk assessment of left ventricular systolic dysfunction in primary care: Cross sectional study evaluating a range of diagnostic tests

Abstract

Objectives. To assess the probability of left ventricular systolic dysfunction without echocardiography in patients from general practice. Design. Cross sectional study using multivariate regression models to examine the relation between clinical variables and left ventricular systolic dysfunction as determined by echocardiography. Setting. Three general practices in Copenhagen. Subjects. 2158 patients aged > 40 years were screened by questionnaires and case record reviews; 357 patients with past or present signs or symptoms of heart disease were identified, of whom 126 were eligible for and consented to examination. Main outcome measures. Clinical variables that were significantly (P < 0.05) related to ejection fraction ≤ 0.45 and their predictive value for left ventricular systolic dysfunction. Results. 15 patients (12%) had left ventricular systolic dysfunction. The prevalence was significantly related to three questions: does the electrocardiogram have Q waves, left bundle branch block, or ST-T segment changes? (P = 0.012); is resting supine heart rate greater than the simultaneous diastolic blood pressure? (P = 0.002); and is plasma N-terminal atrial natriuretic peptide > 0.8 nmol/l? (P = 0.040)? Only one of 60 patients with a normal electrocardiogram had systolic dysfunction (2%, 95% confidence interval 0% to 9%) regardless of response to the other two questions. The risk of dysfunction was appreciable in patients with a yes answer to two or three questions (50%, 27% to 73%). Conclusions. A normal electrocardiogram implies a low risk of left ventricular systolic dysfunction. Patients can be identified for echocardiography on the basis of an abnormal electrocardiogram combined with increased natriuretic peptide concentration or a heart rate greater than diastolic blood pressure, or both.